Derinkuyu: Inside Türkiye's 280-Foot-Deep Underground City

In 1963, a resident of a small Turkish town knocked down a wall in his home and found a passage into Derinkuyu, a vast ancient underground city carved roughly 280 feet (85 meters) into soft volcanic rock beneath Cappadocia. Today, eight of its eighteen floors are open to visitors, making it the deepest underground city in the region accessible to the public.

The sprawling network, which may date as far back as the 8th century BCE, spans about 27,000 square feet and includes stables, kitchens, rock-cut churches, and escape tunnels. Entire communities used it to vanish underground during times of war or religious persecution, sealing themselves behind massive stone doors.

"It is not unique," says Davide Tanasi, archaeologist, professor of history, and associate department chair at the University of South Florida. "Cappadocia has dozens of these, possibly close to two hundred, depending on who is counting and what they count as one." Kaymakli, another well-known underground complex, lies not far from Derinkuyu.

How was Derinkuyu built?

"It was built with hand tools into volcanic ash that had hardened into a soft stone that is easy to cut," Tanasi explains. "It holds itself up without any need for beams or props, so you can keep going without stopping to reinforce anything."

That self-supporting quality allowed builders to expand the complex over centuries. They added levels, systems of shafts, and barrel-vaulted ceilings in some of the larger communal rooms without the structural limitations that typically slow construction down.

How deep does it go?

Derinkuyu reaches approximately 280 feet below the surface, kept livable by vertical air shafts. "They ran from top to bottom of the complex, fifty-two of them," says Tanasi. The shafts drew fresh air into the multi-level complex and extended below the lowest floor to reach groundwater, serving as deep wells.

"Some were deliberately left closed at the surface so that an enemy laying siege could not find them and poison the water," Tanasi adds.

Who built it, and when?

Dating Derinkuyu precisely is difficult. Claims of Hittite or Phrygian origins—roughly the 8th to 7th centuries BCE or earlier—are common but unproven.

"The short version is that nobody can say who first cut into the rock, and the usual answer of Hittites or Phrygians rests on circumstantial evidence rather than anything datable," says Tanasi. Local Christian communities are confirmed to have expanded and used the complex during the Arab raids of the Arab-Byzantine Wars. "After that the network was simply reused by whoever needed it, right up to 1923," he explains.

How many people did it hold?

The oft-cited population figure for Derinkuyu is 20,000, but Tanasi notes there is no visible arithmetic behind it. "The one estimate I have seen that shows its work counted the rooms, noting they average about four square meters and would suit a family of five, and arrived at roughly 2,000 people," he says.

Tanasi agrees the complex was large enough to shelter thousands temporarily, though not designed for year-round living. "The term city for it is probably a tourism word rather than an archaeological one," he adds.

Why was it abandoned?

"It was not abandoned at once," says Tanasi. "It was used, emptied, and used again over many centuries." The Byzantine era marks its most active period, confirmed by archaeological evidence including churches, crosses, pottery, and coins.

Derinkuyu's final chapter came in 1923, when its last residents—the Cappadocian Greeks—were forced out of Türkiye as part of the compulsory population exchange between Greece and Türkiye following the Greco-Turkish war.

How was it discovered?

The 1963 discovery story is remarkable but incomplete. "The upper levels were never lost," says Tanasi. "People in the town had been using them as cellars and storerooms all along, and many still do. The system had been described in print as early as 1916." After its fuller revelation in the 1960s, the government took an interest and began opening the site to visitors.

Can you visit?

Eight of the eighteen total floors are open to the public, including passageways, chambers, ventilation shafts, small chapels, and communal spaces. A full visit usually takes 1.5 to 2 hours.

"It is cool year-round," says Tanasi, "and genuinely tight in places, with steep one-way staircases, so it is a hard visit for anyone claustrophobic or unsteady." Only a fraction of the city is accessible, yet it stands as one of the most extraordinary archaeological sites in the world—and scholars like Tanasi continue to chip away at the question of who first cut into the rock.